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2 Sheets-Sheet 1, B. CRAWFORD. WATER GAUGE 0F BOILERS, &c. No. 8.787. Patented Mar. 9, 1852.

2 Sheets-Sheet 2.

m .& um um RH 00 B FF W AB m A .G R E T A W Patented Mar. 9, 1852.

BENJ. CRAWFORD, or ALLEGHENY orrr, PENNSYLVANIA;

WATER-GAGE or tennis, &c.

Specification of Letters Patent No. 8,787, dated March 9, 1852.

To all whom it may concern; a 1

Be it known that I, BENJAMIN CRAWFORD, of Allegheny city, in the county ofjAllegheny and State of Pennsylvania, have in- Vented a new and useful Improvement in ater-Gages for Steam-Boilers; and I do hereby declare that the following is a full,

clear, and exact description of my said invention, reference bemg had to the accompanying drawings, which form part of th1s specification, and in which Figure 1 is an elevationof the water gage 1n connect-ion wlth one of my lmproved steam gages. Flg. 2 IS a vertical section through Fig.1 and Fig. 3 is an elevation of the lower bend of the tube A.

Float water gages placed in a chamber adjacent to the boiler and communicating therewith by a steam pipe connected to the top and a water pipe connected to the bot-tom of both have heretofore been constructed. This arrangement is liable to such weighty objections as to render its employment inadmissiblefirst, because the sediment in the boiler will seek and settle in the lowest and coolest place, which being the mouth of the water pipe connecting with the gage chamber, the passage between the latter and the boiler will very soon choke up, especially when the boiler is fed with either river or sea water,

and therefore the indications of the gage as to the height of water in the boiler can neverbe relied on without first blowing off the sediment from the connecting pipe through a cock placed at its lowest bend, which would involve an amount of manipulation and inconvenience, entirely incompatible with the use of an instrument of this kind, whose first requisite is reliability as to the correctnessof its indications, and the second is the constant, and conspicuous exposition of the state of the water so that in case of an emergency it can be seen clearly and instantaneously. The blowing ofl involves the frequent agitation of muddy water in the lower part of the gage, which 7 consists of a glass tube and contains the indicator which is seen through the glass. The muddy water thus agitated by blowing 011' causes the sediment to rise and very soon to deposit on the inner surface of the tube an opaque coating, which prevents the indicator from being seen and thus renders the gage useless until taken apart and cleaned, which cannot be conveniently done exceptwhen the fires are out and the boiler chamber that it does in the boiler.

separate chamber adjacent to the boiler and.

communicating therewith, and my invention consists in attaching the glass tube, which forms the lower part of the chamber, to the upper part thereof, at a point, below the water pipe, which connects the chamber with the boiler, the pipe being connected to the boiler some distance from the bottom thereof. By this arrangement the-glass tube is secured from sudden changes of temperature by the rising and falling of the water within it, and it is kept cool, so that the glass is not liable to become corroded or by other means rendered opaque on the inner surface. Thus the indications may at all times be clearly seen, and as the communication with the boiler remains free and open and is not liable to be interrupted the indications can be relied upon with the utmost certainty, and the frequent blowing off of the gage chamber thus dispensed with.

The water gage as shown in the drawings consists mainly of a float D, of a float chamber E, and of an index tube F, to receive the stem j of the float. The float chamber E may be cylindrical. It is connected at its upper extremity with the boiler by a pipe 70 that enters therein above the Water level. Its lower extremity is also connected with the boiler by a pipe Z that enters therein below the water level but above the index tube F, so that the water shall stand at the same level in the float The index tube F appended to the float chamber is made of glass. Its lower extremity is fitted with a cap m, which can be removed when necessary for repairs or other purposes. This cap is provided with a cock which can be .opened at will to blow off the water in the tube whenever the sediment accumulates therein. The float D is fitted to move freely in the float chamber. This float is fitted with a stem j which descends into the glass tube, and is fitted with an in- ;dex i, which rises and falls as the floatrises and falls by an increase or diminution of the water in the boiler. A scale G is attached to the side of the tube to show the level of the Water in the boiler corresponding with that of the index in the glass tube. In a flue boiler that division of the scale corresponding with the level of the water at the tops of the tines should be noted, as shown in the drawing, and the space above this level may be conveniently divided into inches to show the height of the water in inches above the tops of the fiues.

From the above description it is evident that the water in the glass tube will not circulate with that above, as no heat is applied to it, and the hot Water in the float chamber will not descend into it on account of its less specific gravity. Water is well known as so bad a conductor of heat that it -is hardly necessary to state that the water in will permit the rise and fall of the index to be clearly seen. I What I claim as my invention and desire to secure by Letters Patent is The arrangement of the glass index tube below' the point at which the float chamber is connected with the water in the boiler, the water tube connecting with the boiler at some distance from the bottom of the lat- BENJ. CRAWFORD.

Witnesses v v P. H. WATSON, i T. C. DONN- 

